Citation 7.1 - question to fellow owners

I've owned my Citation 7.1 for a month. So far I have been very impressed with the build and sound quality of the amp. In the past I have used Krell 300iL, B&O ICEpower based amps, Theta Intrepid. I found that Citation is the most musical, open, transparent, and smooth sounding of the bunch. The sound coming out from B&W Nautilus 804 is effortless and well balanced in most cases.

I said "in most cases" because I have found that with some recording I noticed rather severe grain, or noise, in the treble. The problem is very specific to the recording, so I might dismiss the problem to be in the recording, not in the equipment. But the problem is that the noise is not heard with my previous equipments. And the nature of the noise is not something that is revealed with more transparent equipment.

The recordings that I hear the grain and noise always have prominent harmonic contents. It's mostly with vibraphones, and sometimes with guitars. Many of my Modern Jazz Quartet albums show this. It's also very noticeable during the guitar intro of Diana Krall's Love Letters, track 2 of Look of Love album. When the guitar notes are strummed, the ringing harmonic of the guitar strings are not very clean. In the listening position it sounds grainy. With my ears next to the tweeter I hear a lot of static-like noise.

If I hadn't noticed this problem I would be very satisfied with the performance of this amp. But this is really a fly in the ointment, and the only reason why I'm searching for other better amps. I wonder if this is a design defect, or a unique problem on my sample. Due to the nature of the rare occurrence of the problem I suspect many of the owners don't even notice this, if this is indeed a design problem. If there is a fellow owner of this amp out there, please give the Diana Krall's Look of Love album a listen, and provide any comment.